U.S. Pat. No. 3,786,314 discloses a current regulating arrangement wherein a precision resistor, a current controlling device and an electromagnetic load are connected in series. The resistor terminal on the side close to the load is then regulated to a predeterminable potential by means of the current controlling device. The voltage drop from the battery voltage applied to the other resistor terminal relative to the predetermined potential generates a specific amount of current flowing through the electromagnetic load. Since in this arrangement the potential controllable by the current controlling device can never become greater than the battery voltage, the flow of current through the load can only be in one direction.
This means that only positive and no negative currents can be generated by means of the current controlling device.